Bromine-methanol etching of semiconductor crystals Cd1-xZnxTe1-ySey with different selenium concentrations

The effect of the selenium concentration in the composition of the Cd1-xZnxTe1-ySey semiconductor crystals on their etching with a bromine-methanol solution was studied. A thermodynamic model is proposed to describe the degree of etching of Cd1-xZnxTe1-y and Cd1-xZnxTe1-ySey crystals. A thermodynamic law is obtained for the first time to describe the change in the etching rate of Cd1-xZnxTe1-ySey crystals with different selenium concentrations. Experimental curves of the etching trajectories and rates of Cd1-xZnxTe1-ySey crystal samples with nominal x ≈ 0.1 and selenium concentrations of y=0, y=0.02, y=0.06, and y=0.1 using 5% bromine-methanol solutions were constructed. The average etching rates were 24 μm/min, 18 μm/min, 15 μm/min, and 13 μm/min. The threshold effect of a strong decrease in the etching rate upon transition from ternary Cd1-xZnxTe1-y to quaternary Cd1-xZnxTe1-ySey crystals, associated with hardening of the crystal structure, was identified and theoretically explained. The obtained experimental data are in good agreement with the theoretical estimates and will be useful for choosing the optimal regimes of crystal treatment.